What types of materials are considered fire-retardant?

Fire-retardant materials are those that have been treated with specific chemicals designed to reduce flammability and slow the spread of fire. These materials undergo a chemical reaction when exposed to heat, forming a protective char that helps to insulate and prevent further ignition. The primary purpose of these treatments is to enhance the safety of various materials, allowing them to perform better under fire conditions.

While some materials may have natural resistance to fire or may be heavy and less likely to ignite, these characteristics alone do not define fire-retardancy. Additionally, not all plastics are categorized as fire-retardant, as they can vary widely in their composition and inherent flammability. Therefore, it is the application of chemical coatings or treatments that specifically designates a material as fire-retardant, making it the most accurate descriptor in the context of this question.